I have a 1976 chev 1/2t 4x4 that has had a factory tachometer added. The problem is while wiring up a new stereo the wire's have come loose on the back of the tach. I just need to know which one goes where. Please help.

Sorry I don’t have any diagrams that old, but it can’t be all that hard to figure out. You’ll have a signal wire from the ignition coil negative and on a HEI system the distributor cap will be marked TACH. A 12-volt feed with the ignition switch in the run position. Possibly a light circuit that will have voltage to it with the parking lights on. Then a ground for the system. After you figure out what wire is what, you should be able to trace the printed circuit on the back of the tach and see where they go. I know I’m simplifying this but a wiring diagram is only going to show you what color wire is what, not where they actually connect to the tach. Dan. Canadian "EH"

This is tough with aftermarket anything. If it happened when a radio was installed I would simply look for wires that are disconnected. Just a shot, - T _________________________________________ Long retired now